Ariston boiler fault codes
Ariston use a three-digit numbering scheme that is more logical than it first appears, because the first digit names the part of the appliance that is complaining. Ariston print the legend in their own manuals: 1 is the primary circuit, 2 the domestic hot water circuit, 3 the internal electronic part, 4 the external electronic part, 5 ignition and detection, 6 air inlet and flue gas outlet, and 7 multi-zone heating. So 108 and 109 are both primary-circuit pressure faults at opposite ends of the range, while anything starting 5 is about flame. Ariston also distinguish a warning from a shutdown by putting a P where the middle digit would be: 5P1 is the warning that the first ignition attempt was unsuccessful, whereas 501 is "no flame detected" and stops the boiler. The one thing to be careful about is that the numbers are not stable across generations. The fan fault is 604 on the Clas HE Evo and 612 on the current One series, and 610 means different things on each, so it is worth knowing which range you have before reading anything as definitive.
Where the code shows on a Ariston
The code appears on the LCD split into a leading digit and a two-digit group, which is why the manual writes it as "1 08" and the display can look like it is showing two separate numbers. Read it as one code. Ariston's newer displays spell the fault out in words alongside the number — "Fault 108 - Filling Needed" is the published example — so the wording on the screen is a better guide than any code list. Warnings, the ones with a P in the middle, appear as an ALERT rather than a fault and the appliance keeps running.
How to reset a Ariston
Press the RESET button on the control panel once. Ariston publish the limit in their own installation manuals, in these words: for safety reasons the boiler will permit a maximum of five resets in fifteen minutes, five presses of the RESET button, and there is a distinct code for having exhausted them — 304, "too many (more than 5) resets in 15 minutes". Exactly what the boiler then requires to come back is not something we have been able to read in Ariston's documentation, so treat the fifth reset as the end of the road rather than counting on a power cycle to buy more. The limit exists to stop a real fault being reset repeatedly instead of diagnosed, and a fault that has survived two resets has told you what you need to know.
Most common Ariston faults
The Ariston codes people look up most.
- 501Get it checkedNo flame was detected during ignition and the appliance has locked out. Check the gas supply and the condensate pipe before booking anyone.
- 108Usually simple to fixThe heating circuit does not contain enough water to run safely. Refill through the filling loop to about 1.2 bar and the code clears.
- 101Get it checkedThe heating circuit has overheated and the appliance has shut down. The usual reason is that water has stopped moving, not that it is firing too hard.
- 103Get it checkedThe appliance is reporting insufficient circulation — water is not moving through it fast enough. Worth acting on before it becomes an overheat.
Every Ariston fault code
7 published codes. Filtering happens in the page — every one is in the HTML.
Showing 7 of 7 codes
Ariston models
Codes can differ between generations. Check yours.
Guides that help with Ariston faults
Boiler fault codes explained: what they actually tell you
Codes look like diagnoses and are not. Understanding which family a code belongs to turns a meaningless number into a genuinely useful starting point.Read the guideHow to repressurise a boiler
The five-minute job that resolves more no-heating calls than any other. Here is how to do it properly, and how to tell when topping up is the wrong answer.Read the guideWhat a Gas Safe engineer actually checks in a boiler service
Most people pay for this once a year and stand in another room while it happens. Here is what should be going on, which test cannot be faked, and how to tell a real service from twenty minutes and an invoice.Read the guideWhat to do when your condensate pipe freezes
The single most common winter boiler fault, and one of the few you can genuinely fix yourself in fifteen minutes with a kettle and some patience.Read the guide
Looking for Ariston’s own support? www.ariston.com. We are not affiliated with Ariston.